I. Field of the Present Invention
The present invention relates generally to viewing devices which enable an occupant of a building to view an exterior area adjacent the building, and more particularly, to such a device which reflects a visual image of the building area directly adjacent to the building wall.
II. Description of the Prior Art
As a security measure, it has previously been known to provide a peephole in a door so that an occupant can view a caller before deciding to open the door and admitting the caller to the premises. Of course, the simplest type of viewing devices is a peephole which permits the occupant to identify a person standing immediately in front of the peephole. Such devices are disadvantageous in that the field of view is limited to the area which is directly in front of the peephole, and thus, the position of the peephole determines the rather limited area which can be viewed. As a result, short people may not be visible through the peephole and faces of taller people may not be visible through the peephole.
One previously known means for increasing the field of view is a viewing device such as that described in U.S. Pat. No. 4,116,529 to Yamaguchi. The device includes a tubular body which is mounted in a door. The exterior end of the housing includes a wide angle lens so that a wide area is reflected rearwardly toward the eyepiece at the other end of the housing. Although such a device substantially increases the range of vision to a person standing at the inside of the door, the angle from which light can be reflected toward the lens is limited such that areas directly below the door and to the sides of the door cannot be viewed. Consequently, a person could stand closely against the side of the building to the side or below the viewing device and remain undetected by the wide angle lens.
Another previously known device which attempts to overcome the blind spots existing in previously known viewing devices is shown in the U.S. Pat. No. 3,973,835 to Miyakawa et al. Miyakawa et al discloses a viewing device having a tubular body which extends through the door and extends past the outer surface of the door. The outwardly extending portion is housed in a clear plastic bubble having a darkened upper surface. The outer, extended portion of the tubular housing further includes a transverse viewing port and reflectively coated glass plate 22 is mounted in the housing at an angle to the viewing port. The reflective plate also extends across a lens secured at the exterior end of the housing. When the housing is rotated so that the viewing port faces the darkened portion of the bubble, no light is reflected in the reflective glass plate and the viewer is able to see through the glass the image reflected through the exterior lens, and is thus able to view the area directly in front of the door. The housing can then be rotated so that the viewing port faces the bottom or a side of the bubble. The light is then reflected by the reflective glass plate toward the viewer so that the viewer is able to see the area directly beneath the viewer or directly to the side of the viewer adjacent the building wall. However, such a device is disadvantageous since the housing must be rotated in order to change the field of vision to provide a view of the area directly below or aside the line of the sight of the viewer. Consequently, all areas adjacent to the door are not simultaneously visible to the occupant. Moreover, the rotational movement of the housing can be detected through the clear plastic bubble and thus, alerts the caller to the fact that the caller is being viewed by an occupant of the building.